This invention relates to a fiber reinforced plastic (FRP) and an indication method thereof.
A policy for improving fuel consumption of a vehicle by a reduction in its weight by replacing metal with plastic of components of the vehicle has been heretofore employed. An FRP product is used for a component which needs a predetermined strength such as a bumper for the vehicle.(e.g., Japanese Patent Laid-Open Publication No. 92756/1990).
On the other hand, in order to economize resources of the earth, a recycling of an FRP product has been conducted. To recycle the FRP product, it is necessary to clearly indicate the material of the FRP product so as to be seen from outside. Heretofore, a method for bonding a printed label printed with the material of the FRP product to the back surface of the FRP product or molding characters for indicating the material of the FRP product in a mold has been employed.
However, when an indication method for a material of an FRP product which has been heretofore conducted is intended to be applied to a hand-lay-up FRP product, following various problems arise.
More specifically, since the hand-lay-up FRP product is molded by alternately hand laying a synthetic resin on a resin-impregnated FRP mat by using only one mold of a front surface side and hardening the back surface of the FRP product by pressure of a roller or a brush, the back surface of the FRP product is rugged which is improper to bond a label or the like, and there arises a problem that, even if a printed label is adhered, the label is frequently peeled.
Furthermore, since a method for molding characters on a back surface of an FRP product in a mold must prepare a special purpose character die, its cost increases, and yet the molded characters are scarcely read by the use for a long period. Thus, in the case of recycling, it is frequently difficult to read the molded characters.
In addition, there also arise problems that both a method for bonding the printed label and a method for molding characters in a mold are difficult to be applied to a curved surface and limited to a flat surface.